Predicted Motif Structure of CRR22 and CRR28.
(A) PPR (or PPR-like), E, and DYW motifs are depicted as boxes with letters. The designation of the P, L, and S corresponds to the PPR motif, PPR-like S (for short) motif, and PPR-like L (for long) motif, respectively, proposed by Lurin et al. (2004). The putative plastid transit peptides are underlined. Sites of Ds or T-DNA insertions in mutant alleles are indicated.
(B) Comparison of the E and DYW motifs among CLB19, CRR4, CRR21, YS1, and CRR2. Alignment was performed using the ClustalW program. The consensus sequence of the E and DYW motifs according to Lurin et al. (2004) is shown at the top. Amino acids that are fully or semiconserved are shaded black and gray, respectively. The invariant Cys and His residues in the DYW motif (Salone et al., 2007) are indicated above the sequences. Amino acids that are conserved among CRR22, CRR28, and YS1 but not in CRR2 are indicated by arrows. The point at which the sequences were truncated in the CRR2ΔDYW, CRR22ΔDYW, CRR28ΔDYW, CRR22ΔEDYW, and CRR28ΔEDYW constructs is specified.